X-ray astronomers are trying to work out a mystery of lightning

Teruaki Enoto (Extreme Natural Phenomena RIKEN Hakubi Research Team, RIKEN) 


Terrestrial gamma-ray flashes (TGFs) are millisecond high-energy radiation from lightning, and studied from outer space by many astronomical satellites. Since 2006, our group, many of which are Japanese X-ray astronomers, has been observing high-energy atmospheric phenomena of lightning and thunderstorms from the ground in Japan. We observationally revealed that electrons can be accelerated to relativistic energies by strong electric fields in thunderstorms and lightning with generating bremsstrahlung radiation and furthermore that photonuclear reactions can be provoked by the gamma rays at lightning discharges [1]. We are now preparing for a new multi-point observation network at Kanazawa supported by the academic crowdfunding and citizen-science framework [2]. Our guiding principle is “collective power of science”. This means a scientific way using multiple detector network instead of a single huge detector. This word also implies scientific collaboration with not only professional researchers but also citizen supporters. We are also planning to launch a series of astronomical CubeSat observatories at RIKEN, starting from a small X-ray CubeSat. 

[1] T. Enoto, Y. Wada, et al., “Photonuclear reactions triggered by lightning discharge”, Nature551, 481 (2017)
[2] Thundercloud Project YouTube https://www.youtube.com/watch?v=ItuR0HOehqk